Multi-stage rapid vaporization apparatus and method

A method for reducing the carbon monoxide content of a gas stream while vaporizing liquid in a fluid stream comprising:

• a) providing a gas stream which comprises carbon monoxide;
• b) providing a fluid stream which comprises liquid;
• c) reacting a portion of said carbon monoxide with oxygen in a exothermic reaction while transferring heat from the exothermic reaction to said liquid in said fluid stream to vaporize said liquid, while maintaining said fluid stream and said gas stream separate from one another;
• d) adding liquid to said vaporized fluid stream;
• e) reacting another portion of carbon monoxide in said gas stream with oxygen in an exothermic reaction while transferring heat from the exothermic reaction to said fluid stream to vaporize said added liquid, while maintaining said fluid stream and said gas stream separate from one another.

A system comprising:

• a vaporizer having an inlet receiving a fluid stream comprising liquid water which is vaporized to form a vaporized outlet stream, said vaporizer comprising at least two heat exchange sections serially arranged in a direction of flow of said fluid stream through said vaporizer for vaporizing liquid in said fluid stream in stages, said heat exchange sections each comprising at least one first channels through which said fluid stream flows and at least one second channel comprising heating means, said first and second channels being separate from one another and arranged in heat transfer relationship with one another;
• a liquid supply means for adding liquid to a downstream heat exchange section of said at least two heat exchange sections, said added liquid mixing with said fluid stream exiting an upstream heat exchange section of said at least two heat exchange sections, for vaporization within said downstream heat exchange section;
• and
• a fuel cell stack in fluid communication with an outlet of said vaporizer, said stack receiving said vaporized outlet stream comprising water for humidifying said stack.